Method for hinging a foldable tablet arm to a stackable chair

ABSTRACT

A Method For Applying Torque To Support Members For A Foldable Tablet Mounted On An Arm Of A Stackable Chair.

Fink Aug. 14, 1973 METHOD FOR HINGING A FOLDABLE 211/150; 29/234. 246

TABLET ARM TO A STACKABLE CHAIR 75 Inventor: Roy w. Fink, Portage, Mich.1 References Cited [73] Assignee: The Vecta Group, Inc., Kalamazoo,UNITED STATES PATENTS Mich r 2,646,106 7/1953 Terry 16/140 3,156,49811/1964 BlOdee 297/162 [22] F1166: Sept. 15, 1972 3,174,795 3/1965Chapman 6: a1 297/160 3,362,669 l/1968 Legge 248/293 [21] APPL 289,4273,467,432 9/1969 Sullivan 297/162 Related US. Application Data [62]Division of Ser. No. 108,511, Jan. 21, 1971, Pat. NO. Examiner-PaulGilliam 3,712,668. Attorney--Raymond H. Blanchard [52] US. Cl 29/434,29/446, 16/140, 57 01 A Method For Applying Torque To Support Members[51] Int. Cl.. B23p 11/00, 323p 11/02, A47b 39/00 52 Field 61 Search297/417, 239, 161, A mdable Tablet Mwmed of A Stackable Chair.

2 Claims, 12 Drawing Figures PAIENIEU Am: 1 4mm sum 2 0; 3

METHOD FOR IIINGING A FOLDABLE TABLET ARM TO A STACKABLE CHAIR This is adivision, of application Ser. No. 108 511 filed Jan. 21, 1971 now U.S.Pat. No. 3,7l2,668

FIELD OF THE INVENTION This invention relates in general to a nestableand gangable tablet arm chair and, more particularly, to a type thereofhaving a hinged tablet arm which is movable from a substantiallyhorizontal operational position into a downwardly and outwardly slopingstorage position which permits stacking of said chair with anothersimilar chair.

BACKGROUND OF THE INVENTION Persons familiar with the use andmanufacture of gangable and stackable chairs, and especially chairs usedin schools, auditoriums and the like, where it is desirable to have atablet arm, are aware that much work and effort have been directed tothe development of a completely acceptable chair capable of meetingthese requirements. However, chairs produced for this purpose to datehave not fulfilled the need due to one or more reasons. That is, eitherthe chair could not be both stacked and ganged if it had a foldabletablet or, if stackable and gangable, the tablet remained in an awkwardposition when in its storage or stacking position. Moreover, it wasfound that stackable tablet arm chairs having movable tablet arms hadsacrificed strength to the extent that they could not be used withoutrisk of early break-down in situations where reasonable, but rough,treatment could be expected.

For example, most of the previous stackable chairs for general purposeuse have had metal legs which have often been tubular. Where a tabletarm was included, the arm supported bracket was either welded or boltedto other parts of the chair, such as the legs. Use of bolts necessitatesopenings which obviously weaken both parts at the point of connection.However, the typical weld is no better..That is, the welding creates anannealed zone with a reduced yield strength, an abrupt and materialchange in cross-sectional area which concentrates stress, and astiffened section which effectively resists distribution of a bendingmoment beyond the change in cross-sectional area. Thus, it comes as nosurprise that failures under stress are most likely to occur at, or evenbe induced by, a typical weld between the legs and arm support bracket.

Accordingly, a primary object of this invention is the provision of astackable and gangable chair having a tablet arm capable of hingedmovement between an operative position and a storage position, saidstorage po sition being such that obstruction to stacking and storage isminimized.

A further object of this invention is the provision of a stackable chairwhich has a hinged tablet arm capable of withstanding abusive use, whichis easy to maintain and is relatively simple in construction.

A further object of this invention is the provision of a device forconnecting a metallic tablet arm support to metallic legs of a chairwhereby the annealing effects of welding are minimized, an abrupt andmaterial change in cross-sectional area is avoided and a substantiallystiff section is eliminated.

Other objects and purposes of this invention will become apparent topersons familiar with chair structures of this type upon reading thefollowing descriptive material and examining the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of achair embodying the invention, same being illustrated in the operativeor use position.

FIG. 2 is a perspective view of said chair in the storage or stackingposition.

FIG. 3 is a front view of a pair of said chairs ganged together, one inthe storage position and one in the operative position.

FIG. 4 is a sectional view taken along line IV-IV in FIG. 3.

FIG. 5 is a fragmentary sectional view taken along the line V--V in FIG.3.

FIG. 6 is a sectional view taken along the line VI-Vl in FIG. 3.

FIG. 7 is a sectional view taken along the line Vll- --VII in FIG. 6.

FIG. 3 is a sectional view taken along the line VIII- VIII in FIG. 2.

FIG. 9 is a broken fragment of FIG. 6.

FIG. 10 is a front elevational view of the pair of chairs in the stackedposition.

FIG. II is a sectional view taken along the line XI-XI in FIG. 10.

FIG. I2 is a sectional view substantially as taken along the line XIIXIIin FIG. 8.

For convenience in description, the terms upper,

lower," front, rear and words of similar import will have reference tothe chair embodying the invention as appearing in FIG. 3 whichillustrates front views of the chair.

' The words right and left will have reference to those sides of saidchair adjacent the right and left sides, respectively, of a personoccupying said chair in a normal manner.

SUMMARY OF THE INVENTION The objects and purposes of the invention,including those set forth above, have been met by providing -a stackableand gangable chair having a folding tablet arm movable between asubstantially horizontal operative position and a downwardly andoutwardly sloping storage or stacking position. The tablet arm ishingedly mounted upon the upper end of a tablet support memher, which inturn is rigidly secured to the legs of the chair. The tabletsupportmember has upwardly diverging arms, and the front chair legsdiverge downwardly with respect to the rear chair legs to permitstacking. Mating ganging members are mounted upon the legs on theopposite sides of the chair, which ganging members are disposedoutwardly of the chair seat whereby stacking is accomplished when thetablet arms are in their storage positions.

DETAILED DESCRIPTION pair of legs 13 and 14 define a substantiallyvertical plane and they are disposed slightly outwardly of the rightedge of the seat 12. The pair of legs 16 and 17 define a substantiallyvertical plane and they are disposed slightly outwardly of the left edgeof the seat. The front legs 13 and 16 preferably define a plane whichslopes downwardly and forwardly relative to the seat 12, and the rearlegs 14 and 17 preferably define a plane which slopes downwardly andrearwardly relative to the seat.

The front legs 13 and 16 are rigidly connected, here integrally, to acenter support portion 18 which extends primarily in the horizontaldirection and which is disposed adjacent to and under the chair seat 12.The rear legs 14 and 17 are also rigidly, here integrally, connected bya center support portion 19 which is disposed adjacent to and under theseat, but rearwardly of the front center support portion 18. Suitablemounting means 21 is rigidly secured to and extends between the centersupport portions 18 and 19, and said mounting means 21 is rigidlyconnected to the chair seat 12.

The chair construction described above may be substantiallyconventional. Further, the downwardly diverging front and rear legs ofthe chair may be formed with their respective center support portionsfrom two pieces of tubing so that they appear as a pair of U- shapedmembers before connection to the mounting means 21.

The chair is provided with a substantially V- shaped tablet arm support22 which is secured to the legs 13 and 14 and opens upwardly. A tabletarm 23 is mounted upon the upper free ends of the front and rear supportelements 28 and 29, respectively, of said tablet arm support 22. Thetablet arm 23 is adapted to be normally disposed in a substantiallyhorizontal position of use, as illustrated in FIG. 1. The tablet armincludes an enlarged front portion 26 adapted to support an article orwriting materials, for example. An elongated arm rest 27 is connected toand extends rearwardly from the front portion 26.

The V-shaped tablet arm support 22 (FIG. 3) is disposed substantiallywithin a vertical plane which is parallel with and outwardly of thevertical plane defined by the right pair of legs 13 and 14. The frontand rear support elements 28 and 29, respectively, (FIG. 6) divergeupwardly and they and inclined forwardly and rearwardly, respectively,to the vertical. The lower ends of the elements 28 and 29 are rigidly,here integrally, connected by a central portion 31, which extendssubstantially horizontally and is disposed at an elevation approximatelymid-way between the upper and lower ends of the chair legs.

The arm support 22 (FIG. 6) is rigidly connected to the legs 13 and 14by means of weld brackets 32 and 32A. Particularly, a first X-shapedweld bracket 32 (FIGS. 6, 7 and 9) is disposed adjacent the point ofintersection of and between the front support elements 28 and the frontlegs 13. The bracket 32 includes a first crossbar 33 which is disposedadjacent to and extends along the front support element 28. Saidcrossbar 33 has a concave outer surface, transversely thereof, whichsnugly embraces the cylindrical support element 28, but othercooperating surfaces could be provided. Said crossbar 33 is connectednear its opposite ends to the leg 13 by welds 34.

The bracket 32 includes another elongated crossbar 35 which is adjacentto and extends along front leg 13. The crossbar 35 is similar tocrossbar 33 and is secured near the opposite ends thereof to the element28 by welds 34.

An X-shaped bracket 32A (preferably a mirror image of bracket 32) isprovided at the intersection of and between the rear leg 14 and the rearsupport element 29 for fixedly interconnecting same. The angle ofintersection between the support elements 28 and 29 and the respectivechair legs 13 and 14 are preferably identical so that the brackets 32and 32A can be mirror images of each other. The crossbars 33, 35 and33A, 35A of the X-shaped brackets are preferably integral so that theyprovide a strong and durable but flexible connector which can be easilyfabricated and formed from sheet metal.

The upper ends of the support elements 28 and 29 are connected to andsupport hinge assemblies 36 and 37, which pivotally connect the tablearm 23 to the V- shaped arm support 22. The hinge axis of the assemblies36and 37 are substantially disposed within the same horizontal plane andare coaxial. The assemblies 36 and 37 are preferably substantiallyidentical to each other so that only the hinge assembly 36 need bedescribed in detail.

The front hinge assembly 36 (FIGS. 2 and 8) includes a stationary hingeplate 38 rigidly secured, as by welding, to the upper end of the frontsupport element 28. The hinge plate 38 is normally substantiallyhorizontal and includes a flange 39 (FIG. 4) extending downwardly alongapproximately three edges thereof. The downwardly extending flange notonly hides the weld seams between the element 28 and plate 38, but alsoimparts additional strength and rigidity to the hinge plate 38 andminimizes sharp edges or comers where they could be injurious. The hingeplate 38 is also provided with a conventional hinge knuckle 41 integralwith an edge thereof.

The hinge assembly 36 includes a movable hinge plate 42 fixedly securedto the underside of the table arm 23 in a conventional manner, such asby means of screws 43, along the straight inner edge 48 thereof. Thehinge plate 42 includes a pair of spaced and conventional hinge knuckles44 integrally connected to the outer edge thereof. The hinge knuckles 44are adapted to be axially aligned with and disposed on opposite axialends of the hinge knuckle 41, so that a hinge pin 46 can be insertedthrough the aligne knuckles in a conventional manner for hingedlyconnecting the hinge plates 38 and 42.

The hinge assembly 36 is also provided with an elongated stop orabutment 47 fixedly secured to, and projecting downwardly from, theunderside of the stationary hinge plate 38. The stop 47, which in theillustrated embodiment comprises a short rod welded to the hinge plate,is parallel with and laterally spaced inwardly from the hinge pin 46.the stop 47 is positioned for engagement by the longitudinal edge 48 ofthe tablet arm 23 to arrest the pivotal movement thereof when it reachesthe storage position substantially as illustrated in FIGS. 8 and 10. Thestop 47 thus prevents the tablet arm from moving into suspended,substantially vertical position, but instead maintains the tablet arm inan inclined stacking or storage position wherein the tablet extends bothdownwardly and outwardly from the hinge axis thereof.

The hinge assembly 37 (FIGS. 2 and 4) has a fixed plate 38A with anintegral knuckle 41A and a movable plate 42A with spaced integralknuckles 44A. A stop 47A is secured to the lower surface of plate 38which has an integral flange 39A.

The chair I is also preferably provided with ganging means forinterlocking a plurality of said chairs in sideby-side relationship andin a row. The ganging means includes male and female ganging members,one being fixedly secured to one side of the chair and the other beingsecured to the opposite side thereof. In the illustrated embodiment, themale ganging member 51 (FIG. 1) is disposed near the right pair of legs13 and M, and it is rigidly connected, as by welding, to the V-shapedtablet arm support 22 near the lower end thereof. The male member 51 isfabricated from metallic rod-like material arranged to fonn a horizontalelongated rectangle. Portions 50 of the member 51 are offset inwardly atthe points of engagement between the member SI and the elements 28 and29 of the tablet arm support 22. This provision spaces the remainder ofthe member 51 away from the tablet arm support so that the femaleganging member 52 can move downwardly past the elements 28 and 29 duringa stacking operation. The opposite substantially rectangular endportions 53 and 54 of the member 51 extend frontwardly and rearwardlybeyond the legs 13 and 14, respectively.

The female ganging member 52 (FIGS. and 6) is fixedly connected to theleft pair of legs 16 and 17. The female member 52 is also fabricatedfrom metallic rodlike material arranged in a horizontally elongatedloop, said member 52 has opposite end portions 56 and 57 which extendfrontwardly and rearwardly beyond the respective legs 16 and 17.

The end portions 56 and 57 on the female ganging member 52 are both bentoutwardly and are substantially perpendicular to the central portion ofthe member 52. These portions 56 and 57 converge upwardly so that theycan overlap the upper comers of the planar end portions 53 and 54 ,of amale ganging member mounted upon a similar, adjacent chair, whereby theto chairs are releasably held in side-by-side relationship.

The exact-structural details of the ganging members 51 and 52, and themanner in which they coact, are explained in greater detail in copendingapplication Ser. No. 79,732, filed Oct. 12, 1970, and entitled IM-PROVED GANGING AND STACKING CHAIR," which application is assigned to theAssignee of this application. I

' While the ganging membersSl and 52 may be secured to the legs 13, 14and l6, 17, respectively, in any convenient manner, projection weldingis preferred, becauseit-minimizes the heat required and/or generated toeffect the weld.

As shown in FIG. 12, the hinge axes 61 and 62 of the hinge assemblies 36and 37, respectively, are preferably at slight angles to the pivotalaxis 63 of the arm 23 before said assemblies are attached to the am. Theamount of the angles may be relatively small, such as about 3 degrees.Thus, just before the hinge plates 42 and 42A are secured to the arm 23,the support elements 28 and 29 are twisted around their length-wise axes(28 counterclockwise and 29 clockwise) until the axis 61 and 62 arecoincident with the axis 63. As a result, the torque applied to theelements 28 and 29 will react to prestress the hinge assemblies 36 and37 whereby friction opposing pivotal movement of the arm 23 is increasedto the point that the am 23 will tend to remain in any position where itis placed between and including those shown in FIGS. I and 2. Thisarrangement improves the safety of the chair in that it avoids theaccidental falling of the arm from a vertical, upright position, asshown in 23C in FIG. 3, into either of the positions at 23 and 23A.

OPERATION The normal position of use for the chair 10, built accordingto the present invention, is illustrated in FIG. ll, wherein the tabletarm is horizontally disposed above one edge portion of, and extendingpartially over, the seat so that the table arm is usable as a supportsurface. Further, if desired, a plurality of identical chairs, such asthe identical chairs l0 and 10A illustrated in FIG. 3, can be ganged inside-by-side relationship to form a row of interconnected chairs.Particularly, the male ganging member 51 provided on the chair I0 isengaged by the female ganging member 52A provided on the chair MIA forinterconnecting the chairs. The engagement of these ganging members isaccomplished (FIGS. 6 and 7) by raising the chair 10A so that the femaleganging member 52A is disposed directly above the male ganging memberSI, after which chair 10A is lowered sothat planar end portions of themale ganging member 51 extend into the sloped end portions formed on thefemale ganging member 52A. This interlocked relationship of the gangingmembers is accomplished when both chairs are resting on the same planarsurface.

Further, with the chairs in the ganged relationship illustrated in FIG.3, each tablet arm 23 can be individually swung around its hinge axisfrom its use position of FIG. 1 into its storage position of FIG. 2 tofacilitate movement of a person into or out of the chair.

When it is desired to stack the chairs one upon another, the tablet arm23 of each chair is first moved into the storage position illustrated inFIG. 2, wherein the tabletarm extends downwardly and outwardly from itshinge axis. The hinged movement of the tablet arm is limited byengagement between the hinge stop 47 and the longitudinal edge 43 of thetablet amt.

With the tablet arms in the storage position, the chairs can be stackedone on top of another substantially as illustrated in FIGS. l0 and Ill.The downward divergence of the front and rear legs, whereby the legs ofan upper chair are disposed above and ride on the legs of a lower chair,prevents said legs from interfering with the vertical stacking. Thelaterally offset location and the V-shaped configuration of the tabletarm supports 22 prevents their interference with the stacking operation.The storage position of the tablet arms is such that they are disposedone above another in the stacked positions, as illustrated in FIG. llll.The vertical nesting of the V-shaped tablet supports is made possible bythe fact that the hinge pin 46 is laterally and outwardly offset fromthe support elements 2% and 29. Thus, when the tablet arm 23 is in thestorage position the tablet support 223 of the chair WB, directly abovechair 110, can pass vertically downwardly between the pair of stationaryhinge plates 33 and 38A on the lower chair 10.

When the chairs are in the stacked position, the weight of an upperchair is preferably transferred to the next lower chair due to bearingengagement between the legs of the two stacked chairs. However, thetablet arm support 22 may also be engaged by the support 228 when thechairs are in stacked positions.

While the chairs illustrated in the drawings are all provided with apivotally movable tablet arm mounted on the side of the chair suitablefor right-handed persons, it will be readily apparent that the presentinvention is also adaptable for so-called lefthanded chairs, that is,chairs having the swingable tablet mounted on the opposite side of thechair.

The bracket 32 (FIGS. 7 and 9) is constructed, and the bars 33 and 35thereof are attached to the element 28 and leg 13, respectively, so thatadverse effects from welds under stress at least minimized. That is, forexample, the bar 33 is welded to the element 28 at two pointssubstantially spaced, such as three or four inches, and each weld can berelatively small, by comparison with a conventional weld which would berequired directly between the leg 13 and element 28, if the bracket 32were not used. The small welds are completely adequate because both thebar 33 and the portion of the element 28 between welds can flex understress, and this greatly reduces the likelihood of a break at the weldwhen a stress is applied to the element 28 or leg 13.

Since the welds are small and produced by a fast acting electricalprocess, annealing is minimized and restricted to the immediate locationof the weld. Thus, there is no extensive, heat affected zone which has alower yield strength and, hence, a lower resistance to failure understress.

The bracket 32 obviously strengthens the adjacent portions of the leg 13and element 28, but it does not create stress concentrations due toabrupt, large changes in cross-sectional area. A stress applied to theleg 13, for example, is distributed along almost the full length of thebar 35 in a manner very nearly corresponding to such distribution if theleg was unattached to the bracket 32 or the element 28.

The brackets 32 and 32A also serve as accurate spacers between the legsand arm support 22 to facilitate stacking or nesting of plural chairs10.

The method of pre-stressing the hinges 36 and 37 (FIG. 12) isaccomplished by applying a torque or torsional deflection to theelements 28 and 29 prior to attachment of their hinges to the arm rest23. The restoring forces within the elements 28 and 29 impose adistortion upon their hinges whereby frictional resistance to themovement of the arm rest can be substantially increased in apredetermined manner.

Although a particular preferred embodiment of the invention has beendisclosed in detail for illustrative purposes, it will be recognizedthat variations or modifications of the disclosed apparatus, includingthe rearrangement of parts, lie within the scope of the presentinvention.

What is claimed is:

1. A method for applying a predetermined amount of frictional resistanceto the pivotal movement of a tablet arm rest pivotally mounted by hingemeans upon a pair of spaced and substantially upright support elements,comprising the steps of:

applying a torque to at least one of said elements;

attaching both of said elements by means of their hinge means to saidarm rest while maintaining the application of said torque, whereby therestoring force in said one element applies a stress upon the hingemeans attached thereto so that said hinge means resists pivotal movementof the arm rest.

2. A method according to claim 1 wherein a torque is applied to theother element before attachment thereof by its said hinge means to saidarm rest.

1. A method for applying a predetermined amount of frictional resistanceto the pivotal movement of a tablet arm rest pivotally mounted by hingemeans upon a pair of spaced and substantially upright support elements,comprising the steps of: applying a torque to at least one of saidelements; attaching both of said elements by means of their hinge meansto said arm rest while maintaining the aPplication of said torque,whereby the restoring force in said one element applies a stress uponthe hinge means attached thereto so that said hinge means resistspivotal movement of the arm rest.
 2. A method according to claim 1wherein a torque is applied to the other element before attachmentthereof by its said hinge means to said arm rest.